Final answer:
With a stuck open expiratory valve, the engine fails to properly compress and expel combustion products, compromising engine performance.
Step-by-step explanation:
If an expiratory valve is stuck open in a constant-volume exhaust system, you will not see the proper compression of the combustion products. Since the exhaust valve is open during the isobaric compression phase, the intent is to push out the remaining combustion products. However, if the valve is stuck open, it negates the ability to build up the pressure necessary to expel these products effectively. This could compromise the engine's performance, as the cycle would be unable to start anew with fresh fuel and air mixture.
For example, if the expiratory valve is stuck open, a person may feel like they are constantly out of breath, as their lungs are unable to fully expand with air during inhalation. Additionally, they may have difficulty performing physical activities that require sustained breath control, such as running or singing.